Forwardly-folding agricultural implements ae relatively widely known as one species of a class of implements that are relatively wide during operation but whose width is decreased for transport by means of folding side or wing sections rearwardly, upwardly or forwardly. The various advantages and disadvantages of each type have been discussed at length in previous patented art and need not be elaborated here. Assignee's U.S. Pat. No. 4,137,852 to Pratt, develops at length one form of forwardly-folding machine. The present invention is an improvement on the Pratt patent.
The Pratt patent discloses what may be termed a three-section machine in which each of the three sections carries agricultural tools, such as planting units for example although the tool bars or sections characteristic of wide implements are not limited to only planting units. In this three-section implement, the three sections, when in operating or field-planting position are transversely alined, end-to-end. The center section is connected to and supported on the drawbar of a tractor by means including a telescopic tongue which is capable of extending as an incident to the forward folding of the wing sections respectively about vertical pivots on the rear section. The wing sections are wheel-supported and relatively easily moved between their transport and folded positions, a characteristic not unknown to rearwardly-folding implements.
According to the present invention, the center section is provided as a wheeled support and does not carry row units or other tools like the wing sections. The wing sections are aligned forwardly of the center section in operating mode; that is to say, there is no center section to intervene between the wing sections. Again a telescopic hitch connection is used to effect folding and unfolding of the implement. An added feature in the present case, however, is that that portion of the rear section, which may include part of the hitch, is selectively variable in length, being rearwardly extendible in the working position of the implement and forwardly shiftable in the folded position of the implement. In other words, when the telescopic hitch is extended in the transport mode, the rear section is moved forwardly to compensate for the increased length of the hitch and achieves a shorter "wheelbase" during transport and improves stability and mobility of the tractor-implement train.
Further features and objects will appear as a preferred embodiment of the invention is disclosed in detail in the following specification and accompanying drawings.